This invention relates to transducers and more particulary to a pressure transducer for use in a feedback control systems for automobile engines for sensing engine manifold vacuum.
Presently, many automobile engines employ a feedback control system for controlling the quantity of fuel and air mixed together and supplied to the engine for combustion. This control is important because it both helps reduce automobile engine pollutions and because it improves engine fuel economy. Typically, the various control strategies employed require sensors to sense various engine operating parameters and develop electrical signals which are supplied to an electronic controller. The electronic controller processes these signals and develops an electrical control signal which, in turn, is provided to an electromechanical device regulating the quantity of fuel mixed with air.
One input required in feedback control strategies is intake manifold vacuum pressure. In many control strategies, a manifold absolute pressure transducer (MAP), is used for this purpose, but the cost of such a transducer is relatively high. Consequently, there is need for a manifold pressure transducer which can be used with the control strategy but which is capable of providing the same information as a manifold absolute pressure transducer at a much lower cost.